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Shock. Scott G. Sagraves, MD, FACS Assistant Professor Trauma & Surgical Critical Care Associate Director of Trauma UHS of Eastern Carolina. Objectives. Define & classify shock Outline management principles Discuss goals of fluid resuscitation

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Shock

Shock

Scott G. Sagraves, MD, FACS

Assistant Professor

Trauma & Surgical Critical Care

Associate Director of Trauma

UHS of Eastern Carolina


Objectives
Objectives

  • Define & classify shock

  • Outline management principles

  • Discuss goals of fluid resuscitation

  • Understand the concepts of oxygen supply and demand in managing shock.

  • Describe the physiologic effects of vasopressors and inotropic agents


Goals
Goals

  • Review hemodynamic techniques in the ICU

  • Introduce the concept of the cardiac cycle

  • Review of the pulmonary artery catheter parameters

  • Utilize the presentation to analyze clinical cases and to feel comfortable with pa-c parameters.


Shock1

Shock:

“A momentary pause in the act of death.”

-John Collins Warren, 1800s


Hypotension
Hypotension

  • In Adults:

    • systolic BP  90 mm Hg

    • mean arterial pressure  60 mm Hg

    •  systolic BP > 40 mm Hg from the patient’s baseline pressure


Definition
Definition

SHOCK: inadequate organ perfusion to meet the tissue’s oxygenation demand.


Hypoperfusion can be present in the absence of significant hypotension

“Hypoperfusion can be present in the absence of significant hypotension.”

-fccs course


Pathophysiology
Pathophysiology significant hypotension.”

ATP + H2O  ADP + Pi + H+ + Energy

Acidosis results from the accumulation of acid when during anaerobic metabolism the creation of ATP from ADP is slowed.

H+ shift extracellularly and a metabolic acidosis develops


Pathophysiology1
Pathophysiology significant hypotension.”

  • ATP production fails, the Na+/K+ pump fails resulting in the inability to correct the cell electronic potential.

  • Cell swelling occurs leading to rupture and death.

  • Oxidative Phosphorylation stops & anaerobic metabolism begins leading to lactic acid production.


Why monitor
Why Monitor? significant hypotension.”

  • Essential to understanding their disease

  • Describe the patient’s physiologic status

  • Facilitates diagnosis and treatment of shock


History
History significant hypotension.”

  • 1960’s

    • low BP = shock; MSOF resulted after BP restored

  • 1970’s

    • Swan & Ganz - flow-directed catheter

    • thermistor  cardiac output

  • 1980’s

    • resuscitation based on oxygen delivery, consumption & oxygen transport balance.


Pulmonary artery catheter
Pulmonary Artery Catheter significant hypotension.”


Pulmonary artery catheter1
Pulmonary Artery Catheter significant hypotension.”

  • INDICATIONS

    • volume status

    • cardiac status

  • COMPLICATIONS

    • technical

    • anatomic

    • physiologic


Placement
PLACEMENT significant hypotension.”


West s lung zones
West’s Lung Zones significant hypotension.”

  • Zone I - PA > Pa > Pv

  • Zone II - Pa > PA > Pv

  • Zone III - Pa > Pv > PA

  • PA = alveolar

  • Pa = pulmonary artery

  • Pv = pulmonary vein


Correct pa c position
Correct PA-C Position significant hypotension.”


Standard parameters

Measured significant hypotension.”

Blood pressure

Pulmonary A. pressure

Heart rate

Cardiac Output

Stroke volume

Wedge pressure

CVP

Calculated

Mean BP

Mean PAP

Cardiac Index

Stroke volume index

SVRI

LVSWI

BSA

Standard Parameters


Why index
Why Index? significant hypotension.”

  • Body habitus and size is individual

  • Inter-patient variability does not allow “normal” ranges

  • “Indexing” to patient with BSA allows for reproducible standard


Index example

PATIENT A significant hypotension.”

60 yo male

50 kg

CO = 4.0 L/min

BSA = 1.86

CI = 2.4 L/min/m2

PATIENT B

60 yo male

150 kg

CO = 4.0 L/min

BSA = 2.64

CI = 1.5 L/min/m2

Index Example


Pa insertion
PA Insertion significant hypotension.”

20

15

10

5

PA 19/10

PAOP = 9

RA = 5

RV = 22/4

0


CVP significant hypotension.”

  • CVP of SVC at level of right atrium

  • pre-load “assessment”

  • normal 4 - 10 mm Hg

  • limited value


PAOP significant hypotension.”

  • End expiration

  • Reflection changes with positive pressure

  • Waveforms change  every 20 cm


Waveform analysis
Waveform Analysis significant hypotension.”

  • A wave - atrial systole

  • C wave - tricuspid valve closure @ ventricular systole

  • V wave - venous filling of right atrium


Cardiac cycle
Cardiac Cycle significant hypotension.”

PVRI

MPAP

pulmonary

PCWP

Right ventricle

Left ventricle

RVSWI

LVSWI

MAP

CVP

systemic

SVRI


Hemodynamic calculations
Hemodynamic Calculations significant hypotension.”

ParameterNormal

Cardiac Index (CI) 2.8 - 4.2

Stroke Volume Index (SVI) 30 - 65

Sys Vasc Resistance Index (SVRI) 1600 - 2400

Left Vent Stroke Work Index (LVSWI) 43 - 62


Cardiac index
Cardiac Index significant hypotension.”

C.I. = HR x SVI

SVI measures the amount of blood ejected by the ventricle with each cardiac contraction.

Total blood flow = beats per minute x blood volume ejected per beat


Vascular resistance index

SYSTEMIC (SVRI) significant hypotension.”

MAP - CVP

CI

 SVR = vasoconstriction

 SVR = vasodilation

PULMONARY (PVRI)

MPAP - PAOP

CI

PVR = constriction

PE, hypoxia

Vascular Resistance Index

x 80

x 80

Vascular resistance = change in pressure/blood flow


Stroke work
Stroke Work significant hypotension.”

LVSWI = (MAP-PAOP) x SVI x 0.0136

normal = 43 - 62

VSWI describe how well the ventricles are contracting and can be used to identify patients who have poor cardiac function.

ventricular stroke work =  pressure x vol. ejected


Too many numbers
Too Many Numbers significant hypotension.”


Definitions
Definitions significant hypotension.”

  • O2 Delivery - volume of gaseous O2 delivered to the LV/min.

  • O2 Consumption - volume of gaseous O2 which is actually used by the tissue/min.

  • O2 Demand - volume of O2 actually needed by the tissues to function in an aerobic manner

Demand > consumption = anaerobic metabolism


Rationale for improving o 2 delivery
Rationale for Improving significant hypotension.”O2 Delivery

Insult

Tissue Hypoxia

Demands are met

Increased Delivery

Increased Consumption


Critical o 2 delivery
Critical O significant hypotension.”2 Delivery

VO2I

The critical value is variable

& is dependent upon the patient, disease, and the metabolic demands of the patient.

DO2I


Oxygen calculations

Arterial Oxygen Content (CaO significant hypotension.”2)

Venous Oxygen Content (CvO2)

Arteriovenous Oxygen Difference (avDO2)

Delivery (O2AVI)

Consumption (VO2I)

Efficiency of the oxygenation of blood and the rates of oxygen delivery and consumption

Oxygen Calculations


Arterial oxygen content
Arterial Oxygen Content significant hypotension.”

CaO2 = (1.34 x Hgb x SaO2) + (PaO2 x 0.0031)

If low, check hemoglobin or pulmonary gas exchange


Arteriovenous oxygen difference
Arteriovenous Oxygen Difference significant hypotension.”

avDO2 = CaO2 - CvO2

Values > 5.6 suggests more complete tissue oxygen extraction, typically seen in shock


Oxygen delivery do 2 i
Oxygen Delivery (DO significant hypotension.”2I)

O2AVI = CI x CaO2 x 10

Normal values suggests that the heart & lungs are working efficiently to provide oxygen to the tissues.

< 400 is bad sign


Oxygen consumption
Oxygen Consumption significant hypotension.”

VO2I = CI x (CaO2 - CvO2)

If VO2I < 100 suggest tissues are not getting enough oxygen


Svo 2
SvO significant hypotension.”2

VO2

SvO2 =

1-

DO2


Oxycalculations
Oxycalculations significant hypotension.”


Resuscitation goals
Resuscitation Goals significant hypotension.”

  • CI = 4.5 L/min/m2

  • DO2I = 600 mL/min/m2

  • VO2I = 170 mL/min/m2

NOT ALL PATIENTS CAN ACHIEVE THESE GOALS

Critically ill patients who can respond to their disease states by

spontaneously or artificially meeting these goals do show a

better survival.


Break time
Break Time… significant hypotension.”


Shock is a symptom of its cause

“Shock is a symptom of its cause.” significant hypotension.”

-fccs course


Signs of organ hypoperfusion
Signs of Organ Hypoperfusion significant hypotension.”

  • Mental Status Changes

  • Oliguria

  • Lactic Acidosis


Components
Components significant hypotension.”


Categories of shock
Categories of Shock significant hypotension.”

  • HYPOVOLEMIC

  • CARDIOGENIC

  • DISTRIBUTIVE

  • OBSTRUCTIVE


Goals of shock resuscitation
Goals of Shock Resuscitation significant hypotension.”

  • Restore blood pressure

  • Normalize systemic perfusion

  • Preserve organ function


In general treat the cause
In general, treat the cause... significant hypotension.”


Hypovolemic shock

Causes significant hypotension.”

hemorrhage

vomiting

diarrhea

dehydration

third-space loss

burns

Signs

 cardiac output

 PAOP

 SVR

Hypovolemic Shock


Classes of hypovolemic shock
Classes of Hypovolemic Shock significant hypotension.”


Treatment hypovolemic
Treatment - Hypovolemic significant hypotension.”

  • Reverse hypovolemia vs. hemorrhage control

  • Crystalloid vs. Colloid

  • PASG role?

  • Pressors?


Resuscitation
Resuscitation significant hypotension.”

  • Transport times < 15 minutes showed pre-hospital fluids were ineffective, however, if transport time > 100 minutes fluid was beneficial.

  • Penetrating torso trauma benefited from limited resuscitation prior to bleeding control. Not applicable to BLUNT victims.


Fluid administration
Fluid Administration significant hypotension.”

  • 1 L crystalloid  250 ml colloid

  • crystalloids are cheaper

  • blood must supplement either

  • FFP for coagulopathy, NOT volume

  • Watch for hyperchloremic metabolic acidosis when large volumes of NaCl are infused

  • NO survival benefit with colloids


Role of pasg
Role significant hypotension.”of PASG?

  • Houston - Higher mortality rate in penetrating thoracic, cardiac trauma

  • No benefit in penetrating cardiac trauma

  • Role undefined in rural, blunt trauma

  • Splinting role


Cardiogenic shock
Cardiogenic Shock significant hypotension.”

  • Cause

    • defect in cardiac function

  • Signs

    •  cardiac output

    •  PAOP

    •  SVR

    •  left ventricular stroke work (LVSW)


Coronary perfusion pressure
Coronary Perfusion Pressure significant hypotension.”

Coronary PP = DBP - PAOP

coronary perfusion =  P across coronary a.

GOAL - Coronary PP > 50 mm Hg


The failing heart
The Failing Heart significant hypotension.”

  • Improve myocardial function, C.I. < 3.5 is a risk factor, 2.5 may be sufficient.

  • Fluids first, then cautious pressors

  • Remember aortic DIASTOLIC pressures drives coronary perfusion (DBP-PAOP = Coronary Perfusion Pressure)

  • If inotropes and vasopressors fail, intra-aortic balloon pump


Distributive shock
Distributive Shock significant hypotension.”

  • Types

    • Sepsis

    • Anaphylactic

    • Acute adrenal insufficiency

    • Neurogenic

  • Signs

    • ± cardiac output

    •  PAOP

    • SVR


Sirs distributive shock
SIRS - Distributive Shock significant hypotension.”

  • Prompt volume replacement - fill the tank

  • Early antibiotic administration - treat the cause

  • Inotropes - first try Dopamine

  • If MAP < 60

    • Dopamine = 2 - 3 g/kg/min

    • Norepinephrine = titrate (1-100 g/min)

  • R/O missed injury


Adrenal crisis distributive shock
Adrenal Crisis significant hypotension.” Distributive Shock

  • Causes

    • Autoimmune adrenalitis

    • Adrenal apoplexy = B hemorrhage or infarct

    • heparin may predispose

  • Steroids may be lifesaving in the patient who is unresponsive to fluids, inotropic, and vasopressor support. Which one?


Obstructive shock
Obstructive Shock significant hypotension.”

  • Causes

    • Cardiac Tamponade

    • Tension Pneumothorax

    • Massive Pulmonary Embolus

  • Signs

    •  cardiac output

    •  PAOP

    •  SVR


Endpoints
Endpoints? significant hypotension.”

  • ACS CoT ATLS - restoration of vital signs and evidence of end-organ perfusion

  • Swan-guided resuscitation

    • C.I.  4.5, DO2I  670, VO2I  166

  • Lactic Acid clearance

  • Gastric pH


Summary
Summary significant hypotension.”

Type PAOP C.O. SVR

HYPOVOLEMIC 

CARDIOGENIC 

DISTRIBUTIVE  or N varies 

OBSTRUCTIVE   


Vasopressor agents
Vasopressor Agents? significant hypotension.”

  • Augments contractility, after preload established, thus improving cardiac output.

  • Risk tachycardia and increased myocardial oxygen consumption if used too soon

  • Rationale, increased C.I. improves global perfusion


Vasopressors inotropic agents

Dopamine significant hypotension.”

Dobutamine

Norepinephrine

Epinephrine

Amrinone

Vasopressors & Inotropic Agents


Dopamine
Dopamine significant hypotension.”

  • Low dose (0.5 - 2 g/kg/min) = dopaminergic

  • Moderate dose (3-10 g/kg/min) = -effects

  • High dose (> 10 g/kg/min) = -effects

  • SIDE EFFECTS

    • tachycardia

    • > 20 g/kg/min  to norepinephrine


Dobutamine
Dobutamine significant hypotension.”

  • -agonist

  • 5 - 20 g/kg/min

  • potent inotrope, variable chronotrope

  • caution in hypotension (inadequate volume) may precipitate tachycardia or worsen hypotension


Norepinephrine
Norepinephrine significant hypotension.”

  • Potent -adrenergic vasopressor

  • Some -adrenergic, inotropic, chronotropic

  • Dose 1 - 100 g/min

  • Unproven effect with low-dose dopamine to protect renal and mesenteric flow.


Epinephrine
Epinephrine significant hypotension.”

  • - and -adrenergic effects

  • potent inotrope and chronotrope

  • dose 1 - 10 g/min

  • increases myocardial oxygen consumption particularly in coronary heart disease


Amrinone
Amrinone significant hypotension.”

  • Phosphodiesterase inhibitor, positive inotropic and vasodilatory effects

  • increased cardiac stroke output without an increase in cardiac stroke work

  • most often added with dobutamine as a second agent

  • load dose = 0.75 -1.5 mg/kg  5 - 10 g/kg/min drip

  • main side-effect - thrombocytopenia


Dilators significant hypotension.”

- inotropes

+ inotropes

Pressors


Summary pressors inotropes
Summary `pressors & inotropes significant hypotension.”

dilator

Dobutamine

Milrinone/Amrinone

Labetalol

Ca+2 blocker

ACE inhibitor

hydralazine

nitroglycerine

Nipride

-dopamine

Isuprel

Digoxin

Calcium

-blocker

- inotrope

+ inotrope

epinephrine

-dopamine

norepinephrine

pressor

neosynephrine


Case studies
Case significant hypotension.”Studies


GSW significant hypotension.”

  • 24 year old male victim of a shotgun blast to his right lower quadrant/groin at close range.

  • Hemodynamically unstable in the field and his right lower extremity was cool and pulseless upon arrival to the trauma resuscitation area.


Shotgun blast
Shotgun Blast significant hypotension.”


Post op
Post-op significant hypotension.”

  • Patient received 12 L crystalloid, 15 units of blood, 6 units of FFP, and 2 6 packs of platelets.

  • HR 130, BP 96/48, T 34.7° C

  • PAWP 8, CVP 6, CI 4.2, SVRI 2700, LVSWI 42.

    Diagnosis? Treatment?


Shock hypovolemia
SHOCK/HYPOVOLEMIA significant hypotension.”

  • FLUIDS… FLUIDS… FLUIDS…

  • BLOOD & PRODUCTS TRANSFUSION

  • CORRECT

    • ACIDOSIS

    • COAGULOPATHY

    • HYPOTHERMIA


MVC significant hypotension.”

  • 38 year old female restrained driver who was involved in a high speed MVC.

  • She sustained a pulmonary contusion and fractured pelvis.


Icu course
ICU Course significant hypotension.”

  • Intubated and monitored with PA-C

  • PCWP = 22, CI = 3.5, SVRI = 2400, LVSWI = 39.8

  • HR = 120, BP = 110/56, SpO2 = 91, UOP = 25 cc/hr

    What do you think...


Hypovolemia

HYPOVOLEMIA significant hypotension.”

ADJUST YOUR WEDGE FOR THE PEEP


Wedge adjustment
Wedge Adjustment significant hypotension.”

  • Measured PAOP - ½ PEEP = “real PAOP”

  • PEEP = 28, therefore “real wedge” = 8


Auto pedestrian crash
Auto-Pedestrian Crash significant hypotension.”

  • Thrown from the rear bed of pick up truck during a MVC at 60 mph.

  • Hemodynamically unstable

  • Pain to palpation of the pelvis

  • Hematuria with Foley® insertion


Icu course1
ICU Course significant hypotension.”

  • Pelvis “closed”

  • QID Dressings, intubated, PA-C inserted

  • PCWP = 20, CI = 5.2, SVRI = 280, LVSWI = 24.5, PEEP = 8

    Diagnosis? Treatment?


Sepsis
Sepsis significant hypotension.”

  • Fluids

  • Correct the cause

  • Antibiotics

  • Debridement

  • Vasopressors

    • Phenylephrine

    • Levophed


Initial resuscitation
Initial Resuscitation significant hypotension.”

  • CVP: 8- 12 mm Hg

  • MAP  65 mm Hg

  • UOP  0.5 cc/kg/hr

  • Mixed venous Oxygen Sat  70%

  • Consider:

    • Transfusion to Hgb  10

    • Dobutamine up to 20 g/kg/min


Vasopressors
Vasopressors significant hypotension.”

  • Assure adequate fluid volume

  • Administer via CVL

  • Do not use dopamine for renal protection

  • Requires arterial line placement

  • Vasopressin:

    • Refractory shock

    • Infusion rate 0.01 – 0.04 Units/min


Steroid use in sepsis
Steroid Use in Sepsis significant hypotension.”

  • Refractory shock 200-300 mg/day of hydrocortisone in divided doses for 7 days

  • ACTH test

  • Once septic shock resolves, taper dose

  • Add fludrocortisone 50 g po q day


Geriatric trauma
Geriatric Trauma significant hypotension.”

  • 70 year old female

  • MVC while talking on her cell phone

  • ruptured diaphragm and spleen s/p OR

  • Intubated and PA-C


Icu course2
ICU Course significant hypotension.”

  • PCWP = 28, CI = 1.8, SVRI = 3150, LVSWI = 20.7

    Diagnosis? Treatment?


Cardiogenic shock1
Cardiogenic Shock significant hypotension.”

  • Preload augmentation - Consider Fluids

  • Contractility

    • dopamine

    • dobutamine

    • phosphodiesterase inhibitor

  • Afterload reduction

    • nitroglycerin

    • dobutamine


Don t forget

Don’t forget... significant hypotension.”

Shock: “rude unhinging of the machinery of life.”

-Samuel D. Gross, 1872


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